Editing Sorbitol (section)

==Synthesis==
<!-- linked from redirect [[Glucose reduction reaction]] -->
Sorbitol may be synthesised via a glucose reduction reaction<ref>{{cite web|title=Reduction of Glucose|url=http://butane.chem.uiuc.edu/pshapley/GenChem2/B8/1.html|website=butane.chem.uiuc.edu|access-date=2017-10-03|archive-date=2017-09-25|archive-url=https://web.archive.org/web/20170925133922/http://butane.chem.uiuc.edu/pshapley/GenChem2/B8/1.html|url-status=dead}}</ref> in which the converted [[aldehyde]] group is converted into a [[hydroxyl]] group. The reaction requires [[NADH]] and is catalyzed by [[aldose reductase]]. Glucose reduction is the first step of the [[polyol pathway]] of [[glucose metabolism]], and is implicated in multiple diabetic complications.  

:{{chem2 | C6H12O6 + NADH + H+ -> C6H14O6 + NAD+ }}

The mechanism involves a [[tyrosine]] residue in the active site of aldehyde reductase. The hydrogen atom on NADH is transferred to the electrophilic aldehyde carbon atom; electrons on the aldehyde carbon-oxygen double bond are transferred to the oxygen that abstracts the proton on tyrosine side chain to form the hydroxyl group. The role of aldehyde reductase tyrosine phenol group is to serve as a general acid to provide proton to the reduced aldehyde oxygen on glucose.

[[File:Glucose reduction to sorbitol.svg|535x535px|Mechanism of glucose aldehyde reduction into sorbitol]]

Glucose reduction is not the major [[glucose metabolism]] pathway in a normal human body, where the [[Blood sugar|glucose level]] is in the normal range. However, in diabetic patients whose blood glucose level is high, up to 1/3 of their glucose could go through the glucose reduction pathway. This will consume NADH and eventually leads to cell damage.